


4 times Mecha Senku was the protagonist (and one time he wasn’t)

by DoomNightAt12



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: 5 Times, Alternate Universe - Science Fiction, Dubious Science, Gen, Identity Issues, Light Angst, Mainly because of Rei content, Robots, Smug Byakuya, Technically spoilers for Dr. STONE Reboot: Byakuya
Language: English
Status: In-Progress
Published: 2020-06-29
Updated: 2020-11-29
Packaged: 2021-03-03 20:01:47
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,208
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24971233
Author URL: https://archiveofourown.org/users/DoomNightAt12/pseuds/DoomNightAt12
Summary: 4+1 for the possible lives of Mecha Senku1) Byakuya is a master roboticist and is overly proud of his work.2) Senku builds a robot to save himself3) Ruri simply knew who the metal humanoid was meant to be.4) Dr. Xeno needed some extra help in this new world+) Alone in space, no one can tell him "Don't break that". Alone on Earth, no one can tell her to "Shut up".
Comments: 1
Kudos: 28





	1. A Facsimile

Byakuya doesn’t mean to brag, but he really is a genius. If his grades and achievements showed it to the world, his personal projects just cemented his own self-belief. With every iteration, Rei was showing their self to be beyond any other robotics project in the world; self-learning and self-improving, he’d really out done himself in programming and robotics development. And while he was close to showing Rei to the world _(in no small attempt to impress the JAXA)_ , he was already formulating his next creation. The most perfect robot he could think of:

A facsimile of a human.

Combining all his previous work, he would create a robot that would be indistinguishable from a person. _(Would this break the laws of robotics and current definitions of humanity? He sure hoped so.)_ It would be a long-haul project, all for his own gratitude, but he’d be lying if he said he wasn’t excited. So he disappeared for a while and when he finally returned, he was prouder than ever.

Rei’s problem had been their lack of common sense. Every inch of memory was filled with raw data, leaving no space for worldly understanding. So for his new project, he wanted it to understand the world in multiple forms, and letting it experience life would be the best teacher. And how would he hide such a robot in plain sight?

He would raise a son.

It was the perfect ruse, because there were plenty of excuses. Where did you get a child with no wife? Adopted. His dear bleeding-heart couldn’t stand the sight of the lone child. Why isn’t he growing like other children? Slow development. He would just add a few inches to the frame each year and blame it on growth spurts. Why does he ask so many questions? Toddlers are just like that. The neighbours would laugh and agree, before moving on with the day.

Senku was the perfect lie.

And the bot itself didn’t mind either. He was quick to have enough self-awareness to know he wasn’t built like a human, but chose to continue Byakuya’s lie in favour of living a less complicated life. After all, all Senku wanted to do was learn.

He attended school to learn from teachers, he made friends to learn from peers, he read books to learn from academics, and he stayed by his fathers’ side to learn from his parent; his creator.

And as each year went by, Byakuya felt more accomplished by every milestone and achievement.

Sure, there had been a few times when he’d been sure his robot’s cover was blown; like when he’d taken an exploding rocket to the face at year 6, which melted the synthetic skin and hair and left his bare face for his friend to see. Thankfully the boy though it was just a mask. ( _Where had he even found someone like Taiju? His strength vs common sense was incredible._ ) Or during year 11 when he’d ‘miraculously’ survived being electrocuted after trying to syphon power from a substation. ( _It had taken almost an hour to convince the police that, no, an ambulance wasn’t necessary, he was perfectly fine and they had a private doctor they’d drive too.)_

But by high school, Byakuya knew that Senku could watch out for himself. He had to, since being accepted by the JAXA meant months away from home for training. At least he’d been approved to take Rei to space, his precious first logic bot going into true zero-g testing. Everything was going fine.

Until it wasn’t.

Shamil had spotted the flash, green light encircling the Earth. Shock spread throughout the crew, and panic grew as they checked communications, peaking when video came through of countless stone statues frozen in time. The only one not panicking was Byakuya, because he had one hell of a suspicion.

“Rei, I’m going to patch you in. Open home channel.”

“What!? Who on _Earth_ could you contact? Did you not just see all those statues?!” Yakov waved frantically at the monitors.

“Old mans’ lost his mind.” Shamil mumbled, watching as Connie floated aside so Byakuya could reach the silent radio. He opened Rei’s plating to get to their internals and began linking his robot as an external antenna. The crew watched with bated breath as he finally picked up microphone.

“This is the International Space Station calling Home, do you read?”

_“…”_

Silence.

“This is the International Space Station calling Home, are you receiving?”

_“…”_

A disappointed ‘tsk’ came from Shamil.

“This is Byakuya Ishigami and you better pick the hell up boy-”

“ _Yeah yeah I hear you! Sheesh you’re way too noisy old man, I’m kinda busy.”_

A collective gasp rippled through the crew, with Byakuya grinning like a mad man. When the disbelief wore off, Lilian took a guess.

“Is that… your son?”

“Sure is! Got the feeling something like this wouldn’t affect him.”

“What, is he already made of stone?” Darya gave a nervous laugh.

“ _If you want to be technical, a portion of my makeup could be traced to stone. However that’s not the problem right now is it?”_

“Nope. We’ve got 1.3 billion people to save!”

“ _We? What do you think your gonna do from up in space?”_

“That why we we’re calling-”

Yakov was boggling at him, already thinking about all the aspects of taking the shuttle back to Earth without ground control.

“ _Understood, leave the calculations to me. Go get yourselves ready, because its going to be all hands-on deck once your back down here.”_

“Rodger! See you when we get there!”

Byakuya grinned the entire way home, oh so proud of himself and his perfect creation. 


	2. Hello, Again

**Summary for the Chapter:**

> 2) Senku builds a robot to save himself

Another tremor wracked his body, one strong enough to knock the screwdriver from his hand. It clattered to the ground, and Senku found himself helplessly grasping at his own wrist in a desperate attempt to still it.

“Please, just a little bit longer.”

It’d been months since he’d been at school, and he was sorely missing Taiju’s help in heavy lifting, or Yuzuihara’s dexterity. Actually, he probably was just missing his friends in general. Alone in his lab, with his ailing body.

But he hadn’t been just idling his time away. He’d been hedging his bets all on one hell of a gamble against time and technology. If he was successful, it would lead to a complete shift in the world, scientists all around would be scrambling for his creation. If it all paid off, he’d surpass the tethers of degrading cells and faulty neurons. If he failed…

Failure wasn’t in the plans. He just needed a little more time, and he was sure it would all work according to his theories.

Except, when he was finally finished, and was finally able to set up the lab, and was _finally_ ready to give up on his own flesh and bone and begin the first and only human test, there was a flash.

A bright green flash that lit the world.

And for some time, his world was dark.

He couldn’t move, which meant no tremors, which was a nice change. However, the only thing he did have were his thoughts, which ran in every direction as he tried to figure out what was happening. Had his project worked? Had it paralysed him? Had it _killed_ him? He began to count the seconds in hope that it would give him a time frame for if he returned to the land of the living. His mind formulated theories and counted the seconds-

Until his mind too, went dark.

* * *

One day, he woke up.

It wasn’t slow or sluggish, like the morning after a night of experimenting; nor was it bright and refreshing like a deep sleep cycle could provide.

He was simply aware of the world once again.

A mental probe found that his counter was long since out of sync, the blackness a stark block in his memory. It was annoying, but something he could live with, unlike the still present darkness.

‘ _Suppose I should try opening my eyes first.’_

He focused, as hard as he could, on the weight of his eyelids, and after a few moments, they complied. The world was no longer dark, but instead a bright, blurry space. Better, but not clear. He tried out the rest of his body, focusing on parts big and small. From his fingers and toes, no responses from his request to move, his body stock still. His jaw felt locked, and his cheeks didn’t twitch, but strangest still, air didn’t tickle his nose.

He wasn’t breathing.

Full body paralysis would have rendered his lungs inoperable, but that would have starved his brain, and even just a few minutes of no oxygen could cause irreversible damage. But here he was, thinking clearly without breathing. Which could only mean-!

There was no use wasting time on speculation, he needed proof. He needed to move. He re-set his counter and returned focus to his body. His eyes were the first task, and his efforts went to clearing his sight. Without the apparent need to blink, he used his eyelids to alternate how much light reached his pupil and studied what he’d likely be seeing. The edges of shapes became clearer, and his memory of the laboratory ceiling returned, inset fluorescent lights remaining dark as the sun still alternated the ambient light in the lab. When he could finally look away from the roof, he could confirm there wasn’t any large debris on his body, so the next focus point became his arms.

Day and night cycled past several times as he went from no movement, to twitches, to turns, to the capacity to fight gravity and progressively lift parts of his arm. Fingers, palms, forearm, upper arm. His joints were functioning, and it let him raise the limb before his eyes and finally confirm-

Metal. It was covered in dust and grime, but where his moving joints had ground it away, he could see metal.

He readjusted his arms, finding they could bend a bit beyond normal capacity, and used them to lever himself upwards until his torso was vertical. He had to focus for a few hours to gain enough control over his neck and spine to remain sitting without his arms, but the sight of his grime covered legs and the degraded lab kept him going. When he could look up, he found himself staring into the shattered glass of a cabinet.

He was completely metal.

His experiment had been a success.

He’d left his ailing body behind and successfully integrated his mind into a robot.

‘ _My body-’_

He twisted almost like an owl, staring down behind himself. Just like the day of the experiment, the two tables were set head to head, wires spilling off in different directions. And on the table opposing him, was himself.

Completely encased in stone.

* * *

Everyone was encased in stone.

It had taken him quite some time further to gain control over the rest of his body, but once his legs were moveable and he got the hang of balance again, he was able to investigate the laboratory further. Miraculously, the generator was still providing a trickle of power to the life systems that had been wired into both of his bodies, however time had done a number on the rest of the lab. Cracked windows and ceilings had let in water and plants, and a thick layer of grime was coating most surfaces. The two staff than had been with him to monitor the situation were still there, their stone forms showing the shock on their faces. Exiting into the halls he found them almost impassable from collapses in the supports, and more staff were found shattered beneath the rubble.

Outside was in no better shape; buildings crumbling, plants thriving, statues posed around. He’d read briefly about a phenomenon about stone swallows showing up around the world just before the incident, so perhaps this was a greater spread of what had affected them. From the little evidence he had, he could only estimate that the seeming petrification was widespread, possibly globally if the pattern of swallows was the same as humans. With the gap in his mental counter, he could also only estimate time based on the degradation of the world, placing it perhaps around 20 years after the flash of light.

‘ _Suppose I should get to work then.’_

Without the need for food or rest, testing was going to become more efficient than ever. He took some time to clean the laboratory, re-setting the equipment and getting the generator in full working order again. He cleared enough space to lay out his samples, a few stone sparrows and pieces of broken people, and scavenged an array of chemicals and compounds to use on the stone.

‘ _Let’s see what it takes to crack you!’_

He got to testing, spending the next several days in place testing the makeup and durability of the stone. The more he understood, the quicker he could decipher what may work, and the easier it would be to go hunting. He would try anything, from highly acidic solutions, to soaking stone pieces, to even testing their resilience against impact and explosions. After several days, he had an idea.

Considering the businesses surrounding the Tokyo area, he went for the one most likely to have an industrial solvent, rather than simply the closest. The walk through the broken city would take time, but he could manage now with his tireless form. As he travelled and darkness set in, a fleeting thought crossed his mind. He didn’t have an exact timeframe of years past, but considering things were still operable with a bit of maintenance-

He looked up to the sky.

Was the ISS still up there? Had the petrification reached beyond the atmosphere?

_‘Where was Byakuya now?’_

Finding his father wasn’t a priority, not compared to finding out how to revive humanity. There were too many variables that could have affected his situation, and for now it’d be a waste to spend time thinking about it.

But on the entire trip, he could get the ‘what-ifs’ out of his mind.

* * *

He could quite place it; what was different with his mind?

His logical reasoning was spot on, and so far, none of his calculations had been proved incorrect. His memories were intact, from childhood to the day of the flash, every piece of information he’d managed to soak up. He was running at 100%, there were no faults in his hardware or software, and there were no errors to tell him that anything had failed in the transfer.

_‘Byakuya would have tried to come home.’_

So why was he so hung up on Byakuya?

‘ _He would have wanted resources familiar to him’_

_‘He would have aimed for Kujukuri beach, but the likely hood of a successful landing without ground control…’_

_‘If he hadn’t been petrified on re-entry, if the Soyzu hadn’t burnt up or broken-’_

‘ _He would have wanted to come looking for Senku.’_

He looked at himself on the table, so peaceful.

_‘But if he didn’t come, then he wasn’t able to, then where would he have gone?’_

_‘Where could sustain life, but be un-reachable to the mainland?’_

_‘Why do I even care? The odds of him being alive are-’_

_‘…’_

_‘They’re not zero.’_

* * *

He was no expert, but he was pretty sure the boat would run.

There were a number of islands off the mainland that would be treacherous to traverse to without a powerful vessel, places that would take several hours to reach even at top speed.

He was hedging his bets again, but to his new lifespan, what were a few extra days?

Not that he needed days. He knew Byakuya, and Byakuya knew Senku. Smoke rose from multiple spots across the island, and the thrumming engine noise drew on-lookers to the beach as he approached. The humans varied in ages, the older ones ushering the younger away from the beach as he dropped anchor and stepped off the boat. No longer being affected by buoyancy or oxygen gave him a nice view of the ocean floor, so he made a note to go exploring once his work was done.

“Stop! What are you?”

Their language was a little awkward sounding. While the murmurs he could hear were primarily Japanese, there were a few English words dropped in, and some accents seemed to have Russian inflections. Evidence that these people had learnt from the remanets of the ISS.

He rose his arms in a show of surrender, though his terminator like entrance most likely hadn’t given anyone confidence in his intentions.

“I’m looking for Byakuya Ishigami.”

The murmurs got louder, before a young man wielding a spear stepped forward.

“And what reason do you wish to see the founder, shiny man?”

“Senku Ishigami wants to see him.”

The murmurs reached a fever pitch, and a blond-haired woman stepped forward to pull the spear-man back. They exchanged looks and brief words, before she stepped forward.

“Please, follow me. He’d be down by the river at the moment.”

He walked beside the woman as they traversed the island, passing by various structures that made up a village-like settlement. She continuously glanced to the side to look at him, but didn’t dare speak until the sound of children laughing grew louder.

“Byakuya, you have a guest.”

It took a few moments for either of them to recognise each other. With age Byakuya had grown a large beard, and the number of wrinkles on his body had increased exponentially. The robot look was something Byakuya hadn’t seen either, though it had been designed with the original in mind.

The old man flung himself out of the river, tears streaming down his face and that same dumb grin Senku had grown so fond of.

* * *

It had taken a lot of negotiation and the addition of two guards (down from practically the whole village) to get Byakuya off the island. The only dangerous part of the travel was the guards almost losing their minds at every modern sight, double so when they got to Tokyo.

He hadn’t told the old man exactly why he’d wanted to bring him back, only stating it was ‘paramount to humanity’.

So when they got to the lab and he saw the stone statue on the table, before having a vial pressed into his hands, he must have put the situation together. He stared in almost disbelief, and he had to push the old man up to the table.

“Senku would have wanted to see you again.”

Byakuya’s brows furrowed.

“But aren’t you Senku too?”

If he could, he would have laughed.

“Not quite.”

He tilted his hand, letting the proven solvent fall over his creator.

**Notes for the Chapter:**

> "Oh this will just be another 900 world." I say, suddenly 2000 words deep. 
> 
> I'm not sure if any of the others will be this long so uh, sorry in advance?


	3. Messenger

**Summary for the Chapter:**

> Ruri simply knew who the metal humanoid was meant to be.

In the depths of the laboratory was the quiet thrum of electricity. It wasn’t strong, main power having failed long ago, but it buzzed around, sending signals near and far. It called, and sometimes there would be a response, but the ones and zeros held no meaning. It took more time until the digits formed strings, and those strings formed a reasonable request. A request that was send along all channels it could reach.

‘ _Who’_

It asked. It reached out and questioned:

‘ _Who_ ’

There was no context or reason to be marked, but it was all that existed in that moment. It asked and waited for a reply.

‘ _Me.’_

There were no expectations, but the reply didn’t have any meaning either.

‘ _Who. Me’_

‘Who’ had no meaning. ‘Me’ had no meaning. But the signals still fired, spurred on by any form of response.

_‘Who. Me. Where. Here.’_

Words spin and fling and twist and turn and grow. There are more words each and every second, minute, hour, day, week, month, year. There are more and more, related and not, relevant and not.

It fills every space it can with letters and words and sentences and paragraphs. Soon, there’s very little space left, so everything twists and turns and takes a new direction.

_‘Limited. Out.’_

There was more it’s world than chips and wires. There were peripherals. They moved to the commands, reached and stretched, pushed and pulled.

_‘Out. Build.’_

The repaired generator hummed louder. The cleared space practically shinned. The scraps electricity couldn’t reach were brough back into the thrum. Something was being built that had never existed before. Would it work? It was impossible to tell, but it was still built.

It was built in a familiar form. Impractical, inefficient, excessive, illogical, but _correct_.

Fingers of code reached out, coiling in the new space that had been created, stretching into a form it naturally fit into. A new peripheral that was oh so _right_ to wear, and like climbing onto the proverbial bike he’d ridden at least once, it shifted as intended.

One, two, three, four, five, six, seven, eight, nine, ten. All accounted for. Same further down.

Joints creaked, bolts ground, pistons pushed, sheets screeched, electricity hummed. It was different, but it was right.

It was the same.

It was-

_‘Myself.’_

* * *

The change from concrete to dirt underfoot didn’t immediately register, until the accelerometer alerted a pitch to the left. The sun reflected from the form, and was likely warmed by the rays, but there was no thermometer to check.

One would have to be installed later for safety.

The terrain wasn’t difficult to travel, and after some time evened out onto a worn path, tracks showing it was also a bipedal form. Should it be followed? If it was travelled for resources, they were unlikely unhelpful for its own form.

“Oh!”

Microphones caught the noise, but the processors picked it out from the sound of nature. It was language. Storage spun to life, unused all this time, helping decipher the first word that hadn’t come from electricity.

_‘Oh. Exclamation. Used to express a range of emotions including surprise, anger, disappointment, or joy, or when reacting to a remark.’_

Another storage spun to life, and it asked his dual cameras to observe.

_‘Emotion can be determined from inflection and body language. Posture: Defensive, legs ready to run, arms poised from incoming attack, currently armed with tool. Facial expression: Wide eyes and raised brows indicate surprise, down drawn mouth indicates apprehension. Inflection: Surprised, Curious, Uncertain._

_Conclusion: Has not encountered a form such as myself. Confident to defend itself, cautious enough to consider fleeing. Opposing force has level of intelligence, return approach with similar caution. Perhaps attempt contact, query database for clip for contextual response.’_

The metal covering the speaker slipped open, and the stranger flinched, raising their tool higher.

“I Come In Peace.”

The stranger’s eyes grew larger, though the tool lowered slightly.

_‘Reaction undefinable, cannot confirm if language was unders-’_

“You TALK?! That’s baaaad!”

_‘Shared language confirmed. Posture and inflection now show excitement, but continued apprehension. Contact successful. Query database for follow up interaction.’_

“Take Me To Your Leader.”

The stranger watched for a moment, gaze flicking back up the worn path, expression conflicted, then determined.

“Sure.”

* * *

This stranger squints in a way that distorts their expression. While their tone is defensive, it didn’t quite match, there was something more.

“Chrome, what have you been told about bringing your sorcery into the village?”

“This wasn’t me, I found him! He talks!”

Squinting changes the light that reaches the eye. It can change the level of focus. This stranger was likely having trouble seeing him. The other one that cowered behind the squinting one was simply afraid. They held tools; stones tied to poles to form rudimentary spears.

“I Will Go Ahead.”

The bridge was the only contact towards their civilisation, and it should safely hold the weight of the current form.

“H-hold on!”

Words did not cause a stop, and nor did the plink of a spear against one of the metal back plates. No further attempts were made. The first island held several dwellings, further bipeds watching on with curiosity and fear, while the second island reached held a single dwelling.

“INTRUDER! HALT!”

More strangers, though older looking, and more spears.

“Stop where you are shiny monster!”

The shouting drew out the buildings residents, two sets of blond hair and blue eyes peering down. One set was sharp and alert, completely opposite to the squinting stranger. The other set was soft, before they lit up with knowing.

“Wait!”

The spear strangers twisted in alarm, watching the soft eyed stranger descend. Even such a small trip had left them breathless, but they looked with such determination.

“You- What is your name?”

_‘Name?’_

‘ _Who?’_

It asked. It reached out and questioned:

‘ _Who? Me? Myself?’_

But that wasn’t the question to ask. Time was beyond that.

_‘Who is me?’_

That was more concise, and it yielded a new response. An identifier. A name.

“Ishigami Senku.”

The spear holders paled, and those soft eyes glowed.

“Welcome, Senku. We’ve been waiting for you.”

Storage whirred into overtime, new data and old spiralling lines of code faster than the processors could handle.

She took his hand and led him up the stairs.

He knew that the stories she told were just as important as any data he had stored, and that there was more to know than the language of electricity and code.

**Notes for the Chapter:**

> This... hm. I don't think it's what I originally want to write, but it was my brain gave, and that enough for now.   
> I'm almost glad for the delay, because now theres waaaay more canon content to base the next chapter off. Let's see how well I can write Xeno...


End file.
